Auflistung nach Autor:in "Sprecher, Christoph M."

Gerade angezeigt 1 - 2 von 2

Comparison of the response of cultured osteoblasts and osteoblasts outgrown from rat calvarial bone chips to nonfouling KRSR and FHRRIKA‐peptide modified rough titanium surfaces
(Wiley, 11/2009) Schuler, Martin; Hamilton, Douglas W.; Kunzler, Tobias P.; Sprecher, Christoph M.; de Wild, Michael; Brunette, Donald M.; Textor, Marcus; Tosatti, Samuele G. P.
Mimicking proteins found in the extracellular matrix (ECM) using specific peptide sequences is a well-known strategy for the design of biomimetic surfaces, but has not yet been widely exploited in the field of biomedical implants. This study investigated osteoblast and, as a control, fibroblast proliferation to novel consensus heparin-binding peptides sequences KRSR and FHRIKKA that were immobilized onto rough (particle-blasted and chemically etched) commercially pure titanium surfaces using a poly(L-lysine)-graft- poly(ethylene glycol) (PLL-g-PEG) molecular assembly system. This platform enabled a detailed study of specific cell-peptide interactions even in the presence of serum in the culture medium; thanks to the excellent nonfouling properties of the PLL-g-PEG surface. Cell-binding peptide sequence RGD in combination with KRSR or FHRRIKA was used to examine a potentially-enhanced or synergistic effect on osteoblast proliferation. Bare titanium and bioinactive surfaces (i.e., unfunctionalized PLL-g-PEG and scrambled KSSR, RFHARIK, and RDG) were used as control substrates. Additionally, in a newly developed experimental setup, freshly harvested bone chips from newborn rat calvariae were placed onto the same type of surfaces investigating size and pattern of osteoblast outgrowths. The findings of the current study demonstrated that the difference in osteoblast and fibroblast proliferation was influenced by surface topography more so than by the presence of surface-bound KRSR and FHRRIKA. On the other hand, in comparison with the control surfaces, osteoblast outgrowths from rat calvarial bone chips covered a significantly larger area on RGD, KRSR, and FHRRIKA surfaces after 8 days and also migrated in an isotropic way unlike cells on the bioinactive substrates. Furthermore, the stimulatory effect of 0.75 pmol cm-2 RGD on osteoblast migration pattern could be enhanced when applied in combination with 2.25 pmol cm-2 KRSR.
01A - Beitrag in wissenschaftlicher Zeitschrift
Fabrication of TiO2‐coated epoxy replicas with identical dual‐type surface topographies used in cell culture assays
(Wiley, 01/2009) Schuler, Martin; Kunzler, Tobias P.; de Wild, Michael; Sprecher, Christoph M.; Trentin, Diana; Brunette, Donald M.; Textor, Marcus; Tosatti, Samuele G. P.
The goal of this study was to reproducibly generate samples with complex surface topographies and chemistries identical to a "master surface" and to test their response in cell culture using rat calvarial cells. Negative replicas of dual-type topography were fabricated using dental impression material with half of the surface exhibiting smooth and rough topography, respectively. Positive epoxy resin replicas were cast from the same negative replica eight times consecutively and coated with a 60-nm thin film of titanium dioxide using a vapor deposition technique. Atomic force microscopy, scanning electron microscopy, confocal white light microscopy, and X-ray photoelectron spectroscopy indicated that TiO2-coated epoxy replicas had surface topographical features and surface compositions nearly indistinguishable from the original titanium master surfaces. The described technique showed high reproducibility over at least eight generations of replication using the same negative replica. Rat calvarial osteoblasts proliferated just as well on dual topography surfaces as on single topography surfaces. The advantage of the dual-type substrates is that they facilitate comparison within a single culture dish, thus eliminating dish-to-dish variation as well as saving material, time and costs compared to the usual method of evaluating surfaces in separate dishes.
01A - Beitrag in wissenschaftlicher Zeitschrift